2NE1 (Korean: 투애니원, IPA: [tʰu.ɛ.ni.wʌn]) was a South Korean girl group composed of Bom, Dara, CL, and Minzy, formed by YG Entertainment in 2009. After appearing alongside boy band Big Bang in the song "Lollipop", a promotional single for LG Electronics, the group rose to fame with the release of their two eponymous extended plays, 2NE1 (2009) and 2NE1 (2011), and two studio albums, To Anyone (2010) and Crush (2014). All peaked at the number one position on the Gaon Album Chart. They also scored nine number one hits on the Gaon Digital Chart, with "Try to Follow Me", "Go Away", "Lonely", "I Am the Best", "Ugly", "I Love You", "Falling in Love", "Missing You", and "Come Back Home".

The quartet simultaneously conducted a similarly successful career in Japan, releasing first a Japanese version of their second EP, Nolza (2011) and following up with the studio albums Collection (2012) and Crush (2014). Following a long-term hiatus, Minzy departed the group in April 2016, while the rest of the group disbanded later that November. Though CL and Dara remain signed to YG Entertainment, Bom's contract was not renewed. Their final single "Good Bye" was released on January 21, 2017.

At the peak of their career and prior to their split, 2NE1 was considered one of the most successful and popular girl groups in South Korea. Having sold 66.5 million records, they are one of the best selling girl groups of all time. Billboard magazine ranked 2NE1 as one of the best k-pop girl groups of the past decade while The New York Times named 2NE1's performance at the Prudential Center in New Jersey as one of the "Best Concerts of 2012".